The present invention relates to riding devices, and more particularly to a therapeutic riding device which treats physical and mental impairments of riders by simulating the motion of a horse in three dimensions.
Hippotherapy is the use of horseback riding to enhance the balance and muscle function of people with neurological disorders. This technique originated in Germany and has been used in the United States since the 1950""s. In the United States licensed physical and occupational therapists have designed hippotherapy treatments for over 26,000 neurologically impaired riders.
Physical therapists have documented the following medical benefits of hippotherapy: decreased spasticity, improved balance, improved coordination, improved gait, improved posture, and improved range of motion. Occupational therapists have reported that hippotherapy improves the organization of the sensory system, increases oral motor control, improves cognition, awareness, and processing, improves hand control, and increases the psycho-social interaction of the rider with the environment.
Unfortunately the cost of boarding, feeding, training, grooming, and caring for a horse for use in hippotherapy has prevented many therapists from utilizing this therapeutic exercise. In fact, due to the lack of a cost-effective hippotherapy treatment method, in conjunction with dwindling insurance reimbursements, many therapy centers simply can not afford to implement a hippotherapy program.
The use of a horse in hippotherapy has several inherent limitations. For example, it is difficult to select and train a horse for hippotherapy. Only about 15% of the available horses in the United States fit the criteria for the proper pelvic, trunk, hip, and leg movements during walking to be of therapeutic value to the rider. If a suitable horse can be found, it must then be trained to accommodate a physically or neurologically impaired rider. This includes desensitization of the horse to the sights and sounds associated with moving wheelchair components, unusual vocalizations or limb movements from the rider, stiff legs and trunk of the rider, an inability of the neurologically impaired rider to shift his/her weight when necessary, and the many volunteers walking beside the horse and possibly holding the rider. Once a horse is selected, most often that horse is kept in a horse arena which may be out-of-town. Having to travel to perform hippotherapy is inconvenient for the caregiver or parent of a neurologically impaired rider. If more than one horse is used for hippotherapy, the anatomical and biomechanical variations between the horses may prevent riders from experiencing the same level of therapy from one treatment session to another.
Often, hippotherapy is limited by weather conditions and the mood of the horse. Rain, lightning, or high winds can startle a horse, requiring immediate dismount of the rider and cessation of the hippotherapy treatment. Also, horses may become agitated from seemingly insignificant incidents such as a piece of paper blowing across the dirt, other horses walking into the arena, sudden movements, or loud noises. In order to prevent a horse from bolting out of an arena with the mounted rider or rearing up onto its hind legs throwing the rider off the saddle, a person leading the horse often needs to tightly control the reins while standing in front of the horse.
Other problems associated with hippotherapy arise due to the condition of the rider. Neurologically-impaired riders often require three to four people at the horse arena to (a) determine the most therapeutic position for the rider receiving hippotherapy, (b) groom and saddle the horse, (c) assist in the transfer to and from the horse, and (d) lead or walk beside the horse. In the event that one or more of these people are absent, the rider often can not safely receive hippotherapy, so treatment must be canceled. Physically or psychologically impaired riders sometimes have weak or no strength in their hands which prevents the riders from forming a good grip onto the horn of a horse""s saddle. Furthermore, riders often have poor balance and coordination. Additionally, it is often difficult for riders to regain control of a startled horse, even if assisted by a therapist. Because some neurologically impaired riders require additional physical support during hippotherapy, an adult often sits on the same horse and holds the patient from behind. This technique, however, puts extra strain on the back of the horse which can cause it injury. If a horse""s back has been injured, no riding will be allowed until the injury has healed.
Finally, hippotherapy carries with it the risk of injury to the rider or to therapists assisting the rider. Therapists may be stepped on or kicked by the horse. Riders may fall off a startled horse, incurring serious injury despite the use of a helmet.
The problems enumerated in the foregoing are not intended to be exhaustive but rather are among many which tend to impair the effectiveness of previously known hippotherapy treatments. Other noteworthy problems may also exist: however, those presented above should be sufficient to demonstrate that hippotherapy treatment in the art has not been altogether satisfactory.
Biomechanical analyses of the three planes of movement which occur as horses walk have provided much information on pelvic movements of an ideal hippotherapy horse. It has been determined that an ideal hippotherapy horse has a walking pace of 60-120 steps per minute. Such a pace is believed to provide for maximum therapeutic value for a rider patient. Analyses of the effects imposed on the rider currently indicate that three dimensional cyclic movement patterns of the horse""s pelvis should be within the following parameters: a lateral pelvic tilt of about 5xc2x0 to about 15xc2x0, with a preferred lateral pelvic tilt of about 10xc2x0. This value was determined by drawing an imaginary line in the y-direction through the posterior aspect of the ileum bone comprising half of the pelvis. As the horse completed push-off and began the swing phase of the hind limb forward, that half of the pelvis tilted out (laterally). A second imaginary line was drawn through the same points on the posterior aspect of the ileum. The angle between these two lines during rotation of the ileum along the z-axis was determined to be about 5xc2x0 to about 15xc2x0 and was called the lateral pelvic tilt.
During limb acceleration (swing phase) the horse""s trunk and pelvis were rotated forward about 3xc2x0 to about 15xc2x0, with an average rotation of about 5xc2x0 to about 8xc2x0 (with the spine as the origin of the angle). Similarly, deceleration of the limb in the stance phase caused rotation of that side of the pelvis in the opposite direction. Schematic representation of this motion can be described as a rotation about the local z-axis at the left pelvis (point B of FIG. 1) of the horse. A clockwise rotation about the z-axis, viewed from above the horse, would result in a pelvic rotation forward. The same clockwise rotation along the local z-axis at the right pelvis (point A of FIG. 1) would result in a pelvic rotation back toward the tail of the horse.
Coupled with the pelvic rotation is a lateral displacement along the x-axis of about 3 cm to about 12 cm. Ideally, 7-8 cm of lateral pelvic displacement would occur. Note that lateral pelvic displacement occurs in the positive x-direction on the left side and in the negative x-direction on the right side of the body. The lateral pelvic displacement was measured at the greatest point of the arc along the local x-axis and was directly related to the size of the pelvis of the horse.
A displacement occurs along the z-axis as the horse loads and then unloads the hind limb. This measurement was recorded by measuring the change in the height of the pelvis from the neutral line between point A and point B (FIG. 1) and (FIG. 16). Depending on the height of the horse, this displacement on the average horse was found to be about 2 cm to about 10 cm, with a preferred value of about 5 cm.
In addition, the horseback rider experiences a cyclic rise and fall of one side of the saddle as the horse""s pelvis tilts up and down in the xy plane. During the swing phase of the right hind limb, the right side of the pelvis undergoes a posterior pelvic tilt (tilts up to allow clearance of the limb). After hoof strike, the limb is decelerating and is aided by an anterior tilt of the horse""s pelvis on that side. This causes the iliac crest to drop downward toward the ground, weighting the limb for greater deceleration. This movement corresponds to a rotation along the local x-axis (FIG. 1 and FIG. 7). Looking toward the x-axis of rotation (left to right), a counterclockwise rotation of the local x-axis corresponds to an anterior tilt of the horse""s pelvis with a lowering of the rider (FIG. 1 and FIG. 2). The anterior tilt occurs in a range of about 2xc2x0 to about 15xc2x0, with a preferred anterior tilt of about 3xc2x0 to about 10xc2x0. Similarly a posterior tilt corresponds to a clockwise rotation along the local x-axis and could occur in the range of about 2xc2x0 to about 25xc2x0, with a preferred posterior tilt of about 3xc2x0 to about 7xc2x0 (FIG. 7).
A therapeutic riding apparatus for simulating three dimensional motion of a horse, in accord with the invention, comprises a split seat with two independent axes of rotation and a plurality of members mechanically coupled to the split seat. The seat is covered with a thick cushioned surface capable of transmitting the three dimensional movements generated from two local axes. The plurality of members drive the split seat in a three dimensional pattern which mimics the three dimensional motion of the torso of the horse upon which the rider is seated.
In accord with one aspect of the invention, the three dimensional pattern includes simulating the number of horse steps per minute, with about 20 to about 200 horse steps per minute being preferred, and about 60 to about 120 simulated horse steps per minute being more preferred. Further, the three dimensional pattern simulates the horse""s cyclic lateral pelvic tilt of approximately ten degrees. Even further, the three dimensional pattern simulates the horse""s cyclic pelvic rotation of about five degrees to about eight degrees with a corresponding lateral pelvic displacement along the x-axis of about seven to eight centimeters. In addition, the three dimensional pattern on each side simulates an upward displacement along the z-axis of about 5 centimeters from the neutral line and a downward displacement along the z-axis to about 5 centimeters below the neutral line for a total excursion of about 10 centimeters. Yet further, the three dimensional pattern simulates the cyclic anterior or posterior tilt of three to ten degrees.
An apparatus for performing hippotherapy, in accord with another aspect of the invention, includes a cushioned split seat configured to support one or two adult riders. Two outer cams are coupled to the seat and are configured to propel the seat in a first set of directions. Two inner cams are coupled to the seat and are configured to propel the seat in a second set of directions. Two innermost cams are coupled to a linkage system to propel the seat in a third set of directions.
In accord with yet another aspect of the invention, the cam pairs are machined to simulate movement in each of three dimensions. The cams in each pair are positioned 180xc2x0 to each other in order to create an alternating movement pattern of the left and right sides of the split seat corresponding to an alternating pattern of a horse""s gait.
In accord with another aspect of the invention, the cam pairs may be substituted for other cam pairs having different eccentricities or other such attributes to change a movement pattern of the seat.
In accord with another aspect of the invention, the degree of movement of each cam pair is not dependent on the other two cam pairs, such that a cam pair could be substituted to provide little to no movement in one dimension without altering the remaining two dimensions of movement.
A riding device, in accord with an alternate embodiment of the invention, includes a cushioned split seat adapted to support one or two adults. Two or more members are configured to drive each half of the seat in two separate three dimensional cyclic patterns that mimic the two movement patterns of the left and right side of a horse in motion.
A hippotherapy device, in accord with another embodiment of the invention, may include a cushioned split seat. An outer member is mechanically coupled to the split seat and is adapted to move one side of the seat forwards and backwards (rotation about the local z-axis). This member is designed in such a way that there is a corresponding opposite and equal movement on the other side. This results in an arc of motion consisting of a lateral pelvic displacement (along the local x-axis). An inner cam set rotates along the local x-axis, but due to its design results in an upward or downward movement of the seat (displacement along the local z-axis). An innermost cam set, when rotated along the local x-axis is kept in contact with the cam follower through tension provided by a spring. The preferred embodiment is a closed track cam system, in which no spring is needed. As the cam follower moves, the angle of a linkage mechanism is increased or decreased, affecting the angle of the seat. When the seat is tipped downward, it corresponds to the anterior tilt of the horse""s pelvis. Similarly, when the seat is tipped upward, it simulates the posterior tilt of the horse""s pelvis during gait. The left and the right cams for each cam pair are custom machined and positioned at 180xc2x0 to each other. In addition, the corresponding member is positioned such that the rotation along each local axes will be equal and opposite corresponding with the movements of the left and right sides of a walking horse. A driving shaft is rotated by a rotational force and is coupled to the outer. inner, and innermost cam pairs and is configured to drive the outer, inner, and innermost members. In a typical embodiment, a motor provides the rotational force.
An apparatus for treating physical and mental impairments of a patient by simulating the motion of a horse, in accord with the invention, may include a cushioned split seat for supporting the patient and if necessary, the therapist. A pair of outer cams is coupled to the seat. A pair of inner cams is coupled to the seat. A pair of innermost cams is coupled to the seat. A motor is coupled to the pair of outer cams and to the pair of inner cams and to the pair of innermost cams. As used herein, the term xe2x80x9cmotorxe2x80x9d refers to an electric, hydraulic, or any other rotational force generator. In preferred embodiments, the motor is an electrical motor. Some advantages of an electric motor include its lightness in weight relative to other motors, relative low cost, potential to utilize batteries in portable situations, and ease of use. Other types of motors may, however, be suitable for manipulating the present invention. For example, it is envisioned that a hydraulic power unit (which may be controlled by an electric motor) driving a hydraulic pump may offer certain advantages in control and manipulation of the speed of the cycles. Similarly, a hydraulic pump could provide power for double acting hydraulic cylinders. Similarly, a pneumatic pump powering a pneumatic motor may also be used to power the present apparatus, depending on a particular application. It is also recognized that the present invention may be controlled by microprocessors, which may offer advantages in manipulating the three dimensional mover, heating pad, or any other elements or added features of the invention. Furthermore, it is envisioned that the movements described in the present disclosure could be controlled by a linear or rotary servo mechanism consisting of a computer numerically controlled unit or other forms of microprocessors with electromechanical actuators, encoders, and tachometers and still be within the scope and spirit of this invention. Advantages to the servo mechanism include the ability to progress the patient to a more challenging degree of motion without exchanging the cams. The servo mechanism would provide an infinite level of control over the degree of motions.
These and other objects, features, and advantages of the invention will be further described and more readily apparent from a review of the detailed description of typical embodiments which follows.